Theories differ as to why the campaign is named after a chubby marsupial, but the preferred explanation is that, like a wombat, Nats leaders have traditionally ambled about on slower, older planes in electorates off the beaten track.

Some Nationals have also joked about how a wombat "eats roots and leaves", but these days they'd rather let that one lie.

His team is trying to hold onto 16 Lower House seats, a number of which are held with very slim margins. The tricky spots are Dawson, Flynn and Capricornia in Queensland, and Cowper and Page in northern New South Wales.

The Nats are also hoping to add to their tally by winning in at least one three-cornered contest.

But the country-based party has problems, and some senior figures say they're at risk of losing a handful of seats, or at least taking a shave in safer ones.

Michael McCormack doesn't have the campaign might and cut-through messaging of his predecessor. He's a more traditional style of Nationals leader — more reserved, and certainly less bolshie. But some colleagues think he's boring.

So it was that he set out on his first wombat trail plagued by leadership speculation, with Mr Joyce and cranky Queenslanders nipping at his heels over their push for a new coal-fired power station.

The SFF are running one Lower House candidate, in Calare, in central west New South Wales. But federal Nationals aren't too worried. They don't think the trend will translate because state issues are more nuanced, and because their federal electorates are generally so large.

Country voters traditionally favour incumbency because they like a familiar face, or someone they can trust. It's why Nationals MPs in those bigger, safer seats will have been notching up plenty of mileage on their odometers.

Things could also get interesting in the south coast seat of Gilmore, where party sources say the state's former agriculture minister Katrina Hodgkinson is "in with a chance" in a three-cornered contest sparked by Liberal Ann Sudmalis's retirement.

The Nationals are also likely to lose their NSW Senate seat, whipping the party down from two representatives two years ago to none.

Seats to watch:

Queensland

A big swing against the Coalition could wipe out a few LNP Nationals in Queensland, where Ken O'Dowd and Michelle Landry are in extremely tight races with Labor. They're sitting on their central Queensland seats of Flynn and Capricornia with margins of 1 per cent and less.

Being 'present' is considered crucial to retaining country electorates. Voters like nothing more than knowing their local member, and trusting them. It's why most rural seat contests involve hand-to-hand combat on local issues.

The Liberals are champing at the bit to take back this once-conservative stronghold, after Ms McGowan famously ousted Sophie Mirabella in 2013. Mrs Mirabella lost because of a grassroots 'Voices for Indi' movement that garnered the backing of rusted-on Nationals who felt she wasn't representing them.

Ms McGowan was popular amongst conservative voters, including farmers. They may be less inclined to throw their support behind the new independent candidate: nurse and midwife Helen Haines.